1. Field of the Invention
The present invention relates, in general, to an apparatus for locking a valve in a closed position and methods for the use thereof. The present invention is particularly suited for locking a gate valve used in the manufacture of silicon wafer chips in a closed position.
2. Description of Related Art
In the manufacture of silicon wafer chips, wafer processing is done within process chamber modules that perform the various processing tasks within a vacuum environment to create circuitry on the chips. The process chamber modules are located within clean rooms and are specifically designed to prevent the accumulation of any amount of foreign material on the chips during manufacture and processing. It is well known the extent to which foreign particles can completely damage a chip.
Specialized valves have been designed for use with process chamber modules. Some prior valves are very compact and particularly suited for maximizing cleanliness within clean rooms. Often, the valves are pneumatically actuated and are very efficient in maintaining high pressure seals of the process modules.
Disadvantageously, during blackouts and other temporary power outages, the actuators of such prior pneumatically actuated valves may drift allowing the valve to inadvertently open. As process chamber modules often utilize highly toxic chemicals to process silicon wafer chips, such drift and inadvertent opening of the valve is highly undesirable, particularly during a power outage when the toxic chemicals cannot be properly purged from the process chamber modules. Additionally, a technician may not appreciate the danger of the toxic chemicals lurking within the process chamber module and attempt to manually open the valve. For example, an unwitting technician may attempt to utilize a portable pneumatic source to open the valve.
What is needed is a method and apparatus for locking a valve which overcomes the above and other disadvantages of known prior valves.